Aspiration system for removing urine discharged by the human body, and liquid sensor therefor

ABSTRACT

An aspiration system for removing urine from the human body comprises a disposable body interface device having a liquid collection chamber. A detachable or permanently attached non-contact liquid sensor disposed outside the liquid collection chamber detects the presence of urine within the chamber. The non-contact sensor is selected from: a capacitance sensor; an ultrasonic sensor; a piezo-resonant sensor; and a temperature sensor.

FIELD OF THE INVENTION

The present invention relates to an aspiration system for use in anaspiration system for removing liquids, discharged by the human body.Aspects of the invention are particularly directed to the problems ofurine removal.

BACKGROUND TO THE INVENTION

Urinary management is of critical need in the acute and long term caresettings. Urinary issues are generally grouped into two primarycategories: failure to drain; and failure to contain. In the case offailure to drain, the patient cannot spontaneously drain urine from thebladder. The general solution to this problem is to catheterize thepatient. In the case of failure to contain, the patient cannot containthe urine within their body until a convenient and expedient time. Whenpatients are not conscious or cognizant, they are typicallycatheterized. Patients who are aware but non-ambulatory often utilize amanual collector for assistance, such as a bedpan, a male urinal, or anadult diaper. These can be cumbersome to use, and sometimes result inspills on or around the patient. Also, such manual collectors mayrequire frequent changes, placing additional burden on caregivers. Whenit is desired to monitor the urine output, very often medical staffcatheterize a patient even when catheterization is not otherwiserequired. Catheterization provides a means by which urine can bemonitored more easily than with a manual collector.

There is a growing problem with nosocomial infections and a highincidence of catheter-related urinary tract infections (UTIs). Catheterassociated UTI is the most common nosocomial infection in hospitals andnursing homes, accounting for up to 40% of all institutionally acquiredinfections, or more than 1 million infections in US hospitals each year.There is considerable pressure on the healthcare and nursing professionto reduce such infection.

U.S. Pat. Nos. 5,002,541, 4,747,166 and 4,631,061 describe human urineaspiration systems. The urine aspiration systems include an electricpump for applying suction to a urinal. The urinal includes a liquidsensor for automatically activating the pump when the presence of liquidurine is detected. The three patents all describe liquid-contact sensorsin the form of electrodes forming a normally open circuit that is closedby electrical conduction through liquid, when the sensor is contacted byliquid. However, there are obvious concerns about the possibility ofelectrical current leaking from the electrodes, through the conductiveurine, to the skin. Moreover, the sensor is necessarily used in closeproximity to the sensitive genital area, increasing the concerns ofleakage of current that is applied by the electrodes.

The last mentioned patent, U.S. Pat. No. 4,631,061, also suggests thepossibility of using at least one pair of optical elements, formed byopposed optical fibres integrated into the liquid passage of the urinalor collection tube to sense the liquid. This is said to avoid electricalcurrents applied to the urinal. However, the design is very expensiveand impractical commercially. It requires at least one pair of opticalelements that are optically aligned in a pad with a beam of lightpassing between the pair of optical elements to sense the presence ofliquid. It also needs an optically transparent window to allow the beamof light to pass through. Any residues or moisture condensation couldeasily cloud the window and falsely trigger the pump to turn on. Theoptical fibres are expensive items, and integrating these into theurinal or tubing increases the cost of the urinal or tubing, which arepreferably disposable for hygiene reasons. Moreover, the electro-opticpart is remote from the urinal, and has to be connected by delicate andexpensive optical fibres, making the system delicate and expensive as awhole.

It would be desirable to improve on prior art designs of aspiratedliquid removal systems, especially in terms of urine detection, in orderto satisfy commercial need and improve customer acceptance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a first embodiment of aspirationsystem for collecting and removing liquid discharged by the human body.

FIG. 2 is a schematic plan view of a pair of briefs as an overgarment.

FIG. 3 is a schematic side view of a second embodiment showing animplementation of a capacitive, ultrasonic or piezo-electric non-contactliquid sensor.

FIG. 4 is a schematic side view of a third embodiment showing animplementation of an electro-optic non-contact liquid sensor.

FIG. 5 is a schematic side view of a fourth embodiment showing animplementation of a temperature, non-contact liquid sensor.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the invention are now described with referenceto the drawings. The same reference numerals are used to depict the sameor equivalent features in each embodiment.

Referring to FIG. 1, an aspiration system 10 for removing body liquiddischarged by the human body generally comprises an aspiration unit 12and a body interface device 14 coupled to the aspiration unit 12 bymeans of a flexible conduit 16. The flexible conduit 16 may be regardedas part of the aspiration unit 12 and/or part of the body interfacedevice 14. The body interface device 14 is configured for fitting to thebody at, or around, the site of discharge of the body liquid desired tobe collected. The body interface device 14 is preferably attachable tothe body by means of an adhesive pad 15 that surrounds the site ofdischarge.

In the case of urine removal, the body interface device 14 is configuredto fit at the genital region of a male or female wearer, or a surgicalurostomy. For females, the body interface device 14 is in the form of asnug-fitting urinal (as illustrated herein). For males, the bodyinterface device 14 is in the form of a male urinal or a condom (notillustrated). For urostomates, the body interface device 14 is in theform of a stoma fitment (not illustrated). The present embodiment isespecially suitable for removing urine, since urine removal is mostchallenging in terms of the volume of the liquid to be removed and thespeed of liquid discharge. This can distance the field of urine removalfrom other liquid collection systems. The speed of response of theaspiration system 10 to detect and remove the liquid is a significantfactor in the ability of the aspiration system 10 to manage a urinedischarge. Also, there are significant challenges in terms of costversus hygiene of the aspiration system 10.

The aspiration system 10 includes a liquid sensor 18 for detecting thepresence of liquid discharged by the body and collected at the bodyinterface device 14. The liquid sensor 18 is preferably a non-contactsensor that is able to detect the presence or proximity of liquidwithout contact with the liquid. The liquid sensor 18 generates anelectrical output signal responsive to proximity of detected liquid. Theelectrical signal is communicated to the aspiration unit 12 by means ofan electrical connector 20. The electrical connector 20 may beintegrated with, or separate from, the flexible conduit 16. Theelectrical connector 20 also supplies power from the aspiration unit 12to power the liquid sensor 18.

The feature of the liquid sensor 18 being a non-contact sensor providessignificant advantages because: (i) the non-contact approachautomatically avoids the concerns about passing an electrical currentthrough the liquid in contact with the skin. Instead, there is no directcontact between the liquid sensor 18 and the liquid; (ii) thenon-contact approach means that the liquid sensor 18 is not contaminatedby touching the liquid. This allows the liquid sensor 18 easily to bereused with a different body interface device 14; and (iii) thenon-contact approach means that the liquid sensor 18 does not itselfhave to be in a sterile condition before use, thus avoiding thedifficulty of, or risk of damage when, sterilizing the aspiration system10 that does interface intimately with the body. The feature of theliquid sensor 18 being coupled to the aspiration unit 12 by anelectrical connector 20 avoids the expense and fragility associated withusing an optical fiber connection.

A preferred feature of the invention is that the liquid sensor 18 isseparate from, or at least separable from, the body interface device 14.The body interface device 14 is a disposable item that may bemanufactured inexpensively, and disposed of after a single use, or alimited number of uses, according to the specific body interface device14. The liquid sensor 18 is more expensive, but is intended to be usedplural times, preferably, with a sequence of different body interfacedevices 14. This enables the aspiration system 10 to be produced andused very cost efficiently, since the disposable components aregenerally low cost. The higher cost components may be used multipletimes, and may require infrequent replacement. In one form, the liquidsensor 18 is a universal device that may be used with any of a pluralityof different types of body interface devices 14, such as a femaleurinal, a male condom, a urostomy body fitment, or a catheter.Optionally, the liquid sensor 18 can be permanently attached to the bodyinterface device 14.

The liquid sensor 18 can take a variety of different forms.

In the embodiment illustrated in FIG. 3, the liquid sensor 18 isselected from: a capacitance sensor; an ultrasonic sensor; and apiezo-electric (or piezo-resonant) sensor. A capacitance sensor detectsproximity of liquid according to changes in the dielectric effect ofliquid proximity, compared to air proximity. The dielectric effectaffects the electric field in the active zone around the sensor, andthus, the effective capacitance in the sensor. The capacitance ismonitored by any suitable capacitance sensing circuit (not shown), suchas an RC oscillator whose oscillation frequency and/or whetheroscillation occurs, is dependent on the value of a resistor incombination with the effective capacitance of the sensor. Theoscillation in turn triggers an output stage, coupled to an outputamplifier, to generate an output signal indicative of liquid presence.The capacitance sensing circuit is preferably disposed near or at theliquid sensor 18 (e.g., as part of the liquid sensor 18 itself), or thecapacitance sensing circuit can be disposed at the aspiration unit 12,or at a point along electrical connector 20. A suitable capacitancesensor and capacitance sensing circuit are described in U.S. Pat. No.5,576,619, the contents of which are hereby incorporated by reference.

The invention has been tested using a capacitance “smart” sensor fromSIE Sensors. The sensor of dimension 35 mm (length)×22 mm (width)×10 mm(height) was affixed to the external wall of a body interface device 14.The sensor detected the presence of two test liquids, water and salinesolution, as soon as the liquid was introduced, and provided anactivation signal to the aspiration unit 12 within milliseconds. Theelectric field from the sensor is able to penetrate a wide variety ofplastic components (e.g., polyethylene (PE), polypropylene (PP) andacrylics), either transparent or opaque, with great sensitivity.

An ultrasonic sensor works using the principle of sonar at theultrasonic frequency range. A transducer is resonated at a set frequencyto convert electric energy into ultrasonic frequency range acousticenergy. The ultrasonic acoustic waves are emitted towards a liquidcollection region. Energy is reflected either from the walls if theregion is empty of liquid, or from liquid if present in the region. Bymeasuring the time delay for reflected waves to arrive, and comparingthis to one or more pre-calibrated time delays taken when the liquidcollection region is empty, the presence of liquid can be reliably andquickly detected. An example of ultrasonic liquid sensor is described inU.S. Pat. No. 3,960,007, the content of which is incorporated herein byreference. A commercially available ultrasonic sensor is made availableby ZEVEX Inc.

A piezo-electric or piezo-resonant sensor also uses high frequency,e.g., ultrasonic energy or acoustic signal, in a similar way to theultrasonic sensor described above. The ultrasonic or acoustic signalcould penetrate either transparent or opaque plastic walls. An exampleof piezo-electric sensor is described in U.S. Pat. No. 3,948,098, thecontent of which is incorporated herein by reference.

The invention has been tested with a piezo-resonant sensor obtained fromGEMS Sensors. The sensor of diameter 40 mm was attached to the externalwall of the body interface device 14, and detected the presence ofliquid as soon as introduced.

With the arrangement illustrated in FIG. 3, the liquid sensor 18 isdisposed outside the body interface device 14, or at least outside aliquid collection region 14 a of the body interface device 14. The bodyinterface device 14 is typically made of plastics, through which thesensing electric field can pass in the case of a capacitance sensor, orthrough which an ultrasonic vibration can pass in the case of anultrasonic and/or piezo-electric sensor. The wall of the body interfacedevice 14 is made suitably thin to provide the sensor with the desiredsensitivity to liquid within the body interface device. Alternatively,the body interface device 14 may include a window portion made ofmaterial through which the electric field or ultrasonic vibration canpass easily if the entire body interface device 14 is not made of such amaterial. In the alternative embodiment illustrated in FIG. 5, thehousing of the body interface device 14 can be shaped into a pocket 26,with or without membrane 24, for receiving and retaining a capacitive,ultrasonic or piezo-electric non-contact liquid sensor 18. Such a designalso increases the interface area between the sensor 18 and the liquidcollection region 14 a of the body interface device 14.

In the alternative embodiment illustrated in FIG. 4, the body interfacedevice 14 is configured for use with an electro-optical sensor. The bodyinterface device 14 comprises a window region 22 made of material thatis transparent to the optical radiation used by the electro-opticalsensor. For example, the optical radiation may be in the infra-redrange, and/or the visible range, and/or ultra-violet range. The term“optical” as used herein means that the radiation lies in a frequencyrange that obeys substantially the laws of optics. The electro-opticalsensor comprises an electro-optical emitter, an electro-opticalreceiver, and sensing circuitry for detecting the presence of liquidaccording to the electrical output of the electro-optical receiver. Thesensing circuitry is preferably disposed at the liquid sensor 18 (e.g.,as part of the liquid sensor 18), or the sensing circuitry is disposedat the aspiration unit 12, or at a point along electrical connector 20.An example electro-optical liquid sensor is described in U.S. Pat. No.4,354,180, the content of which is incorporated herein by reference.

In the further alternative embodiment illustrated in FIG. 5, the bodyinterface device 14 is configured for use with a temperature sensor asthe liquid sensor 18. The body interface device 14 comprises a liquidimpermeable membrane 24 for allowing the temperature sensor 18 to beexposed to an increase in temperature should liquid discharged by thebody (in the current case, urine) come into contact with the membrane24. At the same time, the membrane 24 prevents the sensor 18 from cominginto physical contact with the liquid. The membrane 24 may be made of aheat conductive material, or it may be made of other material that isthin enough (e.g., a film) so as not to provide substantial heatinsulation. The use of a temperature sensor 18 can provide a reliableand quick indication of body liquid exiting the body, without requiringthe sensor to be dispersed over a large area. Liquid, such as urine,exits the body at a temperature of about 37° C., which is notably higherthan ambient room temperature (typically about 23° C.), and also higherthan the ambient temperature of a sensor positioned close to the humanskin (typically about 32° C.).

The presence of liquid may be detected by detecting (i) a rapid changein temperature, such as an increase of 1° C. within two seconds and/or(ii) a temperature rise above a threshold, such as above 36° C.

In the present embodiment, the membrane 24 is shaped like a sockdefining a pocket 26 for receiving and retaining the sensor 18. Such adesign also increases the interface area between the sensor 18 and theliquid collection region 14 a of the body interface device 14. However,the membrane 24 could be a simple window in the wall of the bodyinterface device 14, similar to the window 22, if desired.

It will be appreciated that the different configurations illustrated inFIGS. 3-5 may be intermixed, or used with different liquid sensors, asdesired.

In all of the preceding embodiments, the liquid sensor 18 is separatefrom, or at least separable from, the body interface device 14. Theliquid sensor 18 may be held in an operative position with respect tothe body interface device 14 by a variety of possible arrangements:

(a) In one form, a detachable attachment device (not shown) may be usedfor releasably attaching the liquid sensor 18 to the body interfacedevice 14. For example, the detachable attachment device could comprisea peelable adhesive, or a peelable mechanical fastener, such as Velcro,or a mechanical coupling based on interference fitting, or othermechanical means.

(b) In another form, the sensor could be held in position permanentlyusing a an adhesive, or a mechanical coupling.

(c) In another form, the liquid sensor 18 may be held in the operativeposition by an overgarment (FIG. 2), such as a pair of briefs 30. In theillustrated form, the briefs 30 include a retainer 32 for retaining theliquid sensor 18 in position. The retainer 32 comprises, for example, adetachable attachment device for attaching the liquid sensor 18 to thebriefs 30, or a pocket or sling for receiving the liquid sensor 18. Inan alternative form, the briefs 30 might not include a dedicatedretainer, but may instead embrace the body interface device 14 to holdthe liquid sensor 18 in a recess 26 of the body interface device 14(FIG. 5).

The aspiration unit 12 comprises a power supply 40, an electroniccontrol unit 42, and a suction source 44. The power supply 40 isselected as one or more of: a replaceable battery, a rechargeablebattery, radiation collection panels, and a mains power supply.Preferably, the power supply 40 includes a combination of a rechargeablebattery and a mains power supply; such a combination allows portableoperation when the aspiration system 10 is not connected to a mainspower supply, as well as automatic recharging of the battery when theaspiration system 10 is coupled to a mains power supply. Additionally oralternatively, the power supply 40 includes radiation collection panels,such as photovoltaic panels or cells for generating electricity fromambient light, which can improve autonomy of operation or for chargingthe rechargeable battery. The power supply 40 provides power for theelectronic control unit 42, the liquid sensor 18 (if needed), and anypower needed by the suction source 44. The electric control unit 42 andthe liquid sensor 18 could have a separate power supply from the suctionsource 44. In the present embodiment, the suction source 44 is anelectric pump 44 a that operates under control of the electronic controlunit 42, responsive to detection of liquid by the liquid sensor 18. Thepump 44 a could be a suction device based on diaphragm, peristaltic,volume displacement, spring, gravity, siphon, heat-recoverable metaldrive, or an in-line pump. The flexible conduit 16 is coupled throughthe pump 44 a to a liquid collection chamber 46. The liquid collectionchamber 46 may either be separate from the aspiration unit 12 andcoupled thereto with a suitable connector, or the liquid collectionchamber 46 may be integral with and/or housed in the aspiration unit 12.

When the liquid sensor 18 indicates that no liquid is detected, thecontrol unit 42 controls the pump 44 a in a quiescent state. Either thepump 44 a is deactivated to generate no suction, or the pump 44 a isoperated periodically or at a slow speed to produce low suction (whichmay encourage the body interface device 14 to hug against the skin, andproduce a better seal against the skin).

When the liquid sensor 18 detects the presence of discharged liquid, thecontrol unit 42 activates the pump 44 a to generate suction through theflexible conduit 16 to draw the liquid from the body interface device 14into the liquid collection chamber 46. The control unit 42 may operatethe pump 44 a for as long as liquid continues to be detected by theliquid sensor 18, or for a predetermined time interval after liquiddetection has finished. Once collected by the liquid collection chamber46, the volume of liquid output may be measured, or the liquid may beinspected visually, or sent for biochemical testing or analysis.

In an alternative form, instead of a pump 44 a directly applying suctionto the flexible conduit 16, the suction source 44 may comprise a vacuumchamber charged with a low pressure vacuum, and an electronicallycontrolled valve for controlling application of suction from the vacuumchamber to the flexible conduit 16. A pump may be provided for chargingthe vacuum chamber with the vacuum.

When it is desired to replace the body interface device 14, either forthe same patient or for fitting to a new patient, the liquid sensor 18is separated from a current body interface device 14 and/or briefs 30.The current body interface device 14 and/or briefs 30 are disposed of,and the same liquid sensor 18 is available to be used with a replacementbody interface device 14 and/or replacement briefs 30. In the case wherethe non-contact liquid sensor is permanently attached to the bodyinterface device 14, a quick connector along electrical connector 20 andflexible conduit 16 is equipped to allow for the replacement of bodyinterface device 14.

It will be appreciated that the aspiration system 10 as described hereinprovides significant advantages compared to the prior art, and canaddress or mitigate many of the drawbacks of the prior art, especiallyin terms of efficient detection of liquid without electrical contactwith the body liquid. The disposability of the body interface device,and reusability of the liquid sensor 18 without contact with thedischarged liquid, make the aspiration system 10 very hygienic and costefficient. The aspiration system 10 is also extremely versatile, and asingle aspiration system 10 or different embodiments can have a widevariety of applications. For example, the invention is usable in acutecare, home care, and long term care situations or facilities. Theinvention is usable with wheelchairs, and with bed-bound patients, aswell as being able to be implemented as a fully portable device. Theinvention enables the aspiration system 10 to be discrete, therebypreserving the patient's dignity and privacy. The invention may also beused with catheters, either for detecting liquid (urine) presence in acatheter, or for collecting urine from a short catheter that projects ashort distance from the body into the body interface device 14. Whilethe invention as described is especially suitable for removing urine,the invention may find use for removal of other body fluids andsecretions.

Many modifications, improvements and equivalents to the presentinvention may be made without departing from the spirit and/or scope ofthe invention as claimed.

1. An aspiration system for removing urine discharged by the human body,the aspiration system comprising: a. a body interface device having aliquid collection region for collecting urine discharged by the humanbody; and b. a liquid sensor disposed or disposable adjacent to butoutside the liquid collection region, for detecting the presence ofdischarged urine in the liquid collection region without contact withthe urine, the sensor generating an electrical output indicative ofdetected urine.
 2. The aspiration system according to claim 1, whereinthe body interface device is a disposable device.
 3. The aspirationsystem according to claim 1, wherein the liquid sensor is separate orseparable from the body interface device.
 4. The aspiration systemaccording to claim 1, wherein the liquid sensor is permanently attachedto the body interface device.
 5. The aspiration system according toclaim 1, wherein the liquid sensor is configured to be used a pluralityof times with different body interface devices.
 6. The aspiration systemaccording to claim 1, further comprising an attachment part fordetachably attaching the liquid sensor to the body interface device. 7.The aspiration system according to claim 1, further comprising a garmentwearable over the body interface device, the garment being configured tohold the liquid sensor captive in an operative sensing position adjacentto the body interface device.
 8. The aspiration system according toclaim 7, wherein the body interface device comprises a male or femaleurinal, and the garment comprises a pair of briefs.
 9. The aspirationsystem according to claim 7, further when at least one of the garmentand the liquid sensor comprises a retainer for retaining the liquidsensor captive to the garment.
 10. The aspiration system according toclaim 1, wherein the liquid sensor is selected from: a capacitancesensor; an ultrasonic sensor; a piezo-electric sensor; an electro-opticsensor; and a temperature sensor.
 11. The aspiration system according toclaim 1, wherein the body interface device comprises a pocket or recessfor receiving the liquid sensor adjacent to the liquid collectionregion.
 12. The aspiration system according to claim 1, wherein theliquid sensor is a capacitance sensor, and wherein the body interfacedevice comprises a wall or wall portion made of material through whichthe capacitance sensor can project an electric field.
 13. The aspirationsystem according to claim 1, wherein the liquid sensor is an ultrasonicsensor, and wherein the body interface device comprises a wall or wallportion made of material through which an ultrasonic wave can be passed.14. The aspiration system according to claim 1, wherein the liquidsensor is an electro-optic sensor, and wherein the body interface devicecomprises a wall or wall portion made of material through which opticalradiation can be passed.
 15. The aspiration system according to claim 1,wherein the liquid sensor is a temperature sensor, and wherein the bodyinterface device comprises a membrane for permitting the temperaturesensor to be exposed to the temperature of urine in the liquidcollection region and contacting the membrane.
 16. The aspiration systemaccording to claim 1, further comprising a skin adhesive for releasablyattaching the body interface device to the body.
 17. The aspirationsystem according to claim 1, wherein the body interface device isselected from: a female urinal; a male urinal; a male condom; a urostomybody fitment; and a catheter.
 18. An aspiration system for removingurine discharged by the human body, the aspiration system comprising: a.a body interface device having a liquid collection region for collectingurine discharged by the human body; and b. a liquid sensor disposed ordisposable adjacent to but outside the liquid collection region, fordetecting the presence of discharged urine in the liquid collectionregion without contact with the urine, the sensor being separate orseparable from the body interface device.
 19. An aspiration system forremoving urine discharged by the human body, the comprising: a. a liquidsensor configured to detect urine discharged from the body in theproximity of the sensor without contact with the urine, the sensorgenerating an electrical output indicative of detected urine, and thesensor being selected from: a capacitance sensor; an ultrasonic sensor;a piezo-electric sensor; an optical sensor; a temperature sensor; and b.a brief configured to be worn on the body and to hold the liquid sensorin an operative position at the genital area for sensing urinedischarged by the body.
 20. The aspiration system according to claim 18,further comprising a body interface device having a liquid collectionregion for receiving the urine, and wherein the liquid sensor isdisposed outside the liquid collection region and configured to detecturine within the liquid collection region.
 21. The aspiration systemaccording to claim 19 wherein the brief is further configured to holdthe body interface device in an operative position against the body. 22.The aspiration system according to claim 19, further comprising anaspiration unit responsive to the output from the liquid sensor, andconfigured to generate suction to aspirate liquid from the bodyinterface device when liquid is detected by the liquid sensor.
 23. Theaspiration system of claim 19, wherein the liquid sensor is configuredto detect liquid discharged from the body in the proximity of the sensorwithout contact with the liquid, the sensor being selected from: acapacitance sensor; an ultrasonic sensor; a piezo-electric sensor; andan optical sensor.
 24. The aspiration system of claim 19, wherein theliquid sensor is configured, when disposed adjacent to but outside aliquid collection region of a body interface device for collectingliquid discharged from the body, to detect the presence of liquid in theliquid collection region.
 25. The aspiration system of claim 19, furthercomprising an attachment part for detachably attaching the liquid sensorto a body interface device or to an over-garment.
 26. A method ofpreparing an aspiration system for removing liquid discharged by thehuman body, the method comprising: a. providing a body interface devicehaving a liquid collection region for receiving liquid discharged by thehuman body; b. providing a liquid sensor for detecting the presence ofdischarged liquid in the liquid collection region without contact withthe liquid, the sensor generating an electrical output indicative ofdetected liquid; and; c. providing an aspiration unit couplable to thebody interface device and to the liquid sensor, the aspiration unitbeing operable to generate suction to aspirate liquid from the bodyinterface device in response to detection of liquid by the liquidsensor.
 27. The method of claim 25, wherein the liquid sensor isseparate or separable from the body interface device.
 28. The method ofclaim 25, wherein the liquid sensor is permanently attached to the bodyinterface device.
 29. The method of claim 25, wherein the body interfacedevice is selected from: a female urinal; a male urinal; a male condom;a urostomy body fitment; and a catheter.
 30. The method of claim 25,wherein the liquid sensor is selected from: a capacitance sensor; anultrasonic sensor; a piezo-electric sensor; an electro-optic sensor; anda temperature sensor.
 31. (canceled)